Accrued Liabilities (Details) - Warranty obligations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Warranty obligations [Abstract]
Balance at beginning of year	$ 345	$ 288
Provisions	492	413
Deductions	(448)	(356)
Balance at end of year	$ 389	$ 345